The more I think about the rift between political journalism and Nate Silver, the more it seems that it's one that's fundamentally an issue of epistemology — how journalists know what they know. Here's why I think that's the case.
When we talk about the epistemology of journalism, it all eventually ties into objectivity. The journalistic norm of objectivity is more than just a careful neutrality or attempt to appear unbiased; for journalists, it's the grounds on which they claim the authority to describe reality to us. And the authority of objectivity is rooted in a particular process.
That process is very roughly this: Journalists get access to privileged information from official sources, then evaluate, filter, and order it through the rather ineffable quality alternatively known as "news judgment," "news sense," or "savvy." This norm of objectivity is how political journalists say to the public (and to themselves), "This is why you can trust what we say we know — because we found it out through this process." (This is far from a new observation - there are decades of sociologicalresearch on this.)
Silver's process — his epistemology — is almost exactly the opposite of this:
Where political journalists' information is privileged, his is public, coming from poll results that all the rest of us see, too.
Where political journalists' information is evaluated through a subjective and nebulous professional/cultural sense of judgment, his evaluation is systematic and scientifically based. It involves judgment, too, but because it's based in a scientific process, we can trace how he applied that judgment to reach his conclusions.
Both of those different ways of knowing inevitably result in different types of conclusions. Silver's conclusions are at once much more specific and much less certain than those of the political punditry. The process of journalistic objectivity can't possibly produce that kind of specificity; that's outside of its epistemological capabilities.
This is what David Brooks is saying when he tells Politico's Dylan Byers, "If you tell me you think you can quantify an event that is about to happen that you don`t expect, like the 47 percent comment or a debate performance, I think you think you are a wizard. That`s not possible." There's no place in Brooks' journalistic way of knowing for quantifying the possibility of future events, so he can't see how anyone else can know that, either. It's simply impossible.
Joe Scarborough gets us even closer to the clash between processes of knowing when he tells Byers, "Nate Silver says this is a 73.6 percent chance that the president is going to win? Nobody in that campaign thinks they have a 73 percent chance — they think they have a 50.1 percent chance of winning. And you talk to the Romney people, it's the same thing." How does Scarborough know that Silver's estimate is incorrect? He talked to sources in both campaigns. In Scarborough's journalistic epistemology, this is the trump card: Silver's methods cannot possibly produce more reliable information than the official sources themselves. These are the savviest, highest inside sources. They are the strongest form of epistemological proof — a "case closed" in an argument against calculations and numbers.
The other objection political journalists/pundits have to Silver's process is evident here, too. They don't just have a problem with how he knows what he knows, but with how he states it, too. Essentially, they are mistaking specificity for certainty. To them, the specificity of Silver's projections smack of arrogance because, again, their ways of knowing are incapable of producing that kind of specificity. It has to be an overstatement.
In actuality, of course, Silver's specificity isn't arrogance at all — it's the natural product of a scientific, statistical way of producing knowledge. Statistical analyses produce specific numbers by their very nature. That doesn't mean they're certain: In fact, the epistemology of social science has long been far more tentative in reaching conclusions than the epistemology of journalism. As many people have noted over the past few days, a probability is not a prediction. Silver himself has repeatedlycalled for less certainty in political analysis, not more. But that split between specificity and certainty is a foreign concept to the journalistic epistemology.
TL;DR: Political journalists are skeptical of Nate Silver because they don't understand and don't trust the means by which he knows what he knows. And they don't understand it because it's completely different from how journalists have always known things, and how they've claimed authority to declare those things to the public.
No, even that's TL;DR: When journalistic objectivity is confronted with scientific objectivity, its circuits are fried.

Scientific method is a cruel competitor in the world of ideas. Journalists and commentators have largely grown up in a world free of this sort of competition. Like the medieval priests and village soothsayers through time, they are appropriately terrified of someone who has found a source of data that lets them apply scientific method…because, if the data is good, it is always the best guess….perhaps only least wrong, perhaps dead certain…but the data will help the practitioner know that too. This is simply a world most journalists, free of serious education in science and its methodology, cannot comprehend. In many cases, they CHOSE their profession because it freed them to have opinions and defend them rhetorically, rather than to be bound by the cruel rules of science.

And, of course, Nate is their worst nightmare…he writes pretty well, and explains what we can and can’t know with clarity, modesty, and objectivity. And, absolutely WORST of all, he is demonstrably and measurably RIGHT most of the time….and can analytically dissect where and why he was wrong when he misses. And, unlike most journalists, he is seriously interested in learning from being wrong…so he can get better.

This is not the death of journalism. This is the birth of the opportunity to analyze and comment based on intelligent analysis of objective evidence. Those who embrace it will prosper, and become better for it. Those who don’t should consider the dinosaur and fortune teller to ascertain their future career prospects.